Don, DV, CR road race worthy brakes needed.

[Curt C.]

Currently have the Wilwood heavy duty kit that contains a fixed four pot caliper and 11 inch diameter, .810 thick rotor. This setup is not very good for high speed road courses. Looking at the Baer Claw 12 inch system for the Mustang II setup. I need something that will stand up to moderate 25 minute road race sessions. I would like to stay with 15 inch wheels. Any ideas or recommendations on a front brake kit?

[Excaliber]

I got exactly the same setup, and on the track, it sucks! I installed brake cooling ducts and that helped. Then I went with hi-temp pads (but there terrible for the street when cold) and that helped. But none of that helped ENOUGH! Short twisty track here with a lot of braking.

I'm thinking next step: Vented rotors, same size and style so all my "old" parts still work? Anxious to see what some others thoughts on this issure are!

Ernie

[Double Venom]

Curt,
Hmmm, if Ernie hadn't jumped in I'd start asking what's wrong with your set up? But let me ask anyway. Are the brakes fading, getting a soft or hard pedal?

Have you matched the Master Cylinder with the calipers? Do you have a proportioning valve?

I strongly suggest you do NOT use cross-drilled rotors! (Want a personal story? Just let me know )

Baer or Wildwood? We use em both. Baer has a beautifull setup though, bolt on that does work well. Biggest part is matching up the right parts for the system, lightweight calibers, vented and slotted rotors, and of course brake pads, brake pads, brake pads!
Fluid is critical! We've boiled the best of em!


You may have to go through three or four sets of pads to find the ones that work for you. It IS imperative that you either buy the burnished pads, (already broken in) or pay particular attention to the brake in period/instructions.

We can set you up with either styles, but call and talk to Jay at the shop, he is "the" brake destructor! 740-852-5280

DV...I love the smell of burnt fuel, smoking tires, slipping clutches and HOT brakes! If it ever turns into a job I quit!

[Excaliber]

So Curt, what kind of symptoms do you get when the brakes go away?

Myself, the pedal is hard like a rock, doesn't sink at all, just no brakes! I got the high temp Wilwood fluid, it's not getting to hot. I think the rotors/pads are just totally "heat soaked" and thats why the brakes are gone.

You think?

Ernie

[Curt C.]

I run the corvette master (recommended by DV & Don), versailles rear disc brakes with Porterfield carbon kevlar pads; proportioning valve; polymatirx D pads up front; cooling ducts; Wilwood 570 fluid and Goodyear stock car slicks. Slowing down from 120 mph can take a rather long time - too long in my opinion. Brake fade is present. I just think that the little 10 3/4 diameter, .810 thick rotor does not offer enough leverage or thickness (ability to cool). Wilwood has a kit for the MII with a 12.19 rotor, part # 140-7017. However, I did a search and saw where DV did not recommend going higher than 11 inch because they can bend stock MII arms. It appears that the 12.19 rotor will fit 15 inch rims. There has to be a way to get better braking without retrofitting the front suspension and or going to larger rims.

Edit: No cross drilled rotors! learned my lesson warping a set in a Mustang that is street driven only!

[Excaliber]

Yup,,,,were in the same boat all right!

Again your specs are virtually identical to mine, with one or two exceptions. My stopping power BEFORE they start to fade is great, you GOT to have a tight seat belt! I never tried but I think I could darn near lock up the tires even at high speed. Four wheel disc, by the way, prop valve setup with a lot of bias toward the rear. THEY lock up first depending on "load" factors (helps on some of the tight corners I have to deal with). I'm running a stock Ford master cylinder.

I get VERY little warning the brakes are about to go! THATS the scary part, their good, good and then BAM there gone! Almost hit the wall the first time or two that happened, before I figured out how to "feel" them going away.

Is your pedal staying hard? What about 11" rotor but VENTED?? Hate to spend the money and find out it was only a "moderate" gain in performance! Been there done that all ready!

Ernie

[Bill E]

You can run two calipers on your rotor. and a wide roater whit drectshnal vains Colman has them. Then like the man said Pads pads .One set for low timp and a high timp set for the same wheel. We did all this then whet to 17" wheels and 13" rotors man what a difference. Bill E

[Excaliber]

Bill, that should generate enough braking force to "break" the Mustang II suspension. Have you run into that problem? I DO have the lower "stock" arm with upper tubular arm.

16" rims on mine.

Ernie

[Double Venom]

Curt,
#1 - this is an excellent thread! Curt, please send me (us) the link where you mentioned that I mentioned the controls arm being bent. I can't remember that one.

Ernie, usually if you have the brakes you indicate at the start but then go away as they get hot, it is almost always pads.

Bill, That is one heck of an idea! I've never thought about using two different sets of pads. That really brings up questions.

DV...A hydraulic/brake engineer once told me brakes are nothing more than "black science"!

[Curt C.]

DV, here is the old thread.

http://www.clubcobra.com/forums/t241...-&pagenumber=2

While you do not state large discs will break suspension parts, you do recomend using tubular pieces. Breakage was disucssed earlier in the thread so I assumed your recommendation of tubular pieces was a confirmation.

So, will a Mustang II stock setup with good ball joints hold up with a 12.19 rotor?? I have to believe the 12.19 wilwood kit is virtually the same as the heavy duty kit (10.75 rotor) except for different bracket and of course larger rotor.

[Double Venom]

Ahh,
the old memory cells are still there! What I was referring to was old, rusted original-OEM control arms could possibly FLEX and most likely will. On the other hand, new imported Mustang II arms, in my opinion, could also flex. Thusly the recomendation that you go with some serious control arms.

Bill, Jay and I discussed your use of dual calibers at length today. We have to know more!
DV...

[Curt C.]

OK, what Wilwood polymatrix pad would you recommend for the track? Bill's dual caliper idea is interesting. Would this not also put excessive stress on MII parts? By the way, what exactly happens when the arms flex? Have you ever actually seen this happen?

[Ken Greene]

wouldn't two calipers per disc put excesive heat into the discs, pads and what not???

[Excaliber]

As I understand "brakes" (and I'm STILL learning a LOT) the biggest advantage to a multiple piston caliper is threshold braking. The ability to modulate the braking action without locking up the wheels.

Following this logic, multiple calipers (or 6 pot vs 4 vs 1 pot calipers for instance) would allow a driver greater control at the threshold.

But how about this: One caliper with the extreme heat pads for ultra high rotor temps and one caliper with low temp pads?

High temp pads do NOT work well until they get hot! NOT good for the street. So the low temp caliper provides initial braking (like for an auto X run when rotor temps are low). The second set of pads (high temp) START working on the "open track" events when the temps go up.

HOW in the world you would BOLT twin calipers up, plumb them to the master cylinder etc leaves me baffled!

More braking power with "twins"? Not really, more "control" with twins! You could still "lock up" the tires with a single pot and the right "brakes".

Ernie

[Curt C.]

I want to stop like a Z06 Corvette...

[rdorman]

stop like a Z06............

Brakes are a lot more than desire. You can not have what is not available. There are reasons that none of us will ever overcome to stop 'like a z06'. You don't have the weight, you don't have the contact patch(probably), you don't have the lack of compliance, you don't have vertical force.............. the list goes on. But, I am sure, reasonably, that it could be better!

You say fade is ever present. What type of fade? Aside from fade, tell me what else you don't like.

Work with me and you will be much happier. Change this and that will only lead to frustration.

You mention larger rotors. The only thing larger rotors will give you is a unbalanced system (unless you adjust it out or it was wrong in that direction in the first place), lower peddle effort (maybe) and perhaps and increase in pad fade temp.

Stop changing parts. Be specific! realize that it WILL take effort on your part. It WILL take time. It WILL come with no simple answers. It WILL take compromise. Unless of course budget is no consideration!

Side note, no reason to cross drill rotors in your situation. The tend to crack, they lower mass (bad for what you are trying to cure), same effect can be had with out the dark side!

Rick

[Curt C.]

Rick,

The main problem is that after 10-15 minutes on the track, the car simply will not stop effectively in my opinion. I find myself getting on the brakes much earlier and using the engine to help slow the car down. Not sure how to be anymore specific. I want to be more confident and be able to go a little deeper into the turns. I have not purchased any parts yet and I am prepared to invest time in this because I like it. However, if it is the consensus here that I do have enough invested in hardware to stop adequately, maybe I should experiment with pads. I am confident that all my parts are properly matched and in good working order. The "D" pad that I am currently using is basically a street pad with the highest cold friction rating. They say it is good over a wide range of temps. The "B" pad is supposed to be much better for higher temps but like Ernie stated, not too good for the street. I have no problem switching pads before a race.

[rdorman]

We could go through the whole design process or we can start just by looking at the issues. I would enjoy working through this with you. I get a real kick out of this $hit!

Let me ask a couple of questions:

Non-racing temperatures
- are you able to lock all four wheels
- is the amount of pressure required on the peddle to lock all four wheels to your liking
- do the front tires lock first

Now answer the same three questions for the situation you described after 10-15 minutes on the track.

- when the brakes go away, is the peddle still high and hard or does it get spongy
- is your proportioning valve adjustable? if so, who is it made by and where in its range is it set
- please describe in some detail the layout of your ducting.
- have you checked you tire temperatures and if so what do they run after the problem you described. if not, please do so!
- have you noticed any pad taper

Some notes on your pads. The D compound begins to fall off at 600 degrees. That is not very hot. I have used the J compound with a good deal of sucess. Its torque curve is very flat to over 1300 degrees. At that point you rotors will glow red. I don't have my formulas in front of me but it will not take long to reach 600 degrees.

By the way, I have a bedded set of J pads for sale. But before you consider them, lets work through this. Also as a note of interest, the J compound has a higher torque value (CF) cold than the D compound or even the cold stoppers (tan pads). The statement about high temp pads not working when cold is NOT always true.

For all the big wheel, big brake advocates....... the ONLY thing that a larger rotor will do is increase the mechanical torque available. This means that for a given rate of deceleration your peddle effort will be lower. The other thing is IF the mass is greater, the temperature rise will be slower. That is all folks!

Get ahold of True Choice (www.truechoice.com) and get some temperature paint, pads and use them at the next event. It will provide us with information that would take hours of calculations to even some close to!

Hang in there and we will have you stopping on a dime!

Rick

[Cobra University]

Curt, here's my experience...
It is possible the "D" frictions are incorrect for your application. Their effective heat range may be too low for you.

The Polymatrix D type says..."Specifically formulated for performance street and moderate to heavy dirt track use, Polymatrix "D" brake pads provide immediate and predictable response at low to medium temperatures."

If you are running slicks or race tires, you NEED a high-temp pad - MINIMUM! Slicks and race tires will introduce massive heat into your brake pads (because they are grippier to the road than street tires). The superior traction of a race tire generates severe heat in the brake pads, especially if you are coming down from "120mph". (Over 1200+ degrees)

The "D" Pads would be okay for the heat range generated by street tires and medium "open-tracking/autocrossing", but you WILL NOT be able to overpower the crazy heat generated by your Goodyear Slicks, and the pads will die in 10 minutes of competition.

This reminds me of my experience using Hawk Blue 9012, then changing to HT-10. My application had too much heat for Blue 9012. Check out the heat ranges here... http://www.porterfield-brakes.com/hawk.html

I see you are running the Porterfield carbon/Kevlar pads in the rear. Why not try Porterfield R4 pads up front as well? I also agree with the guys on using street pads on the street, then change out to race pads when heading to the track.
And make sure fresh air is getting to the front calipers via minimum 2" duct hose.

Hope this helps!

[Curt C.]

OK! If you want more details on the current setup I can supply them. Answers to your questions:

- I can lcok all four wheels. I have not attempted to lock the brakes up past 60 mph because it frightens the hell out of me. I have Wilwood proportioning valves plumbed into each line. Tuned so fronts lock first. The best tune actually is to have both completely open - full pressure.

-Ducting - I bought some ducts and hose from stock car products.com. The ducts tuck very nicely behind the stock brake vent openings. See attached pic for more info. The hose is not very close to the rotor. Sway bar and steering tie rods prevent getting any closer.

-Peddle is still firm when fade comes on.

-Tire temps. With the stock car slicks, tire temps range from 150 - 170.

-I have not checked for pad taper. How does one check this?

By the way, regarding the Z06 comment - A man needs to have lofty aspirations

Pads, Pads, pads..... After futher study of the Wilwood pad information coupled with everyones comments, I think I need to try a different pad.